package cn.tedu.sp06.fb;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

/*调用商品服务失败时执行这里的降级代码，返回降级结果*/
@Component
public class ItemFB implements FallbackProvider {
    /*针对哪个后天服务调用失败，应用当前降级类
    * 返回值：
    *       “item-service”  只针对商品服务降级
    *       *               针对所有服务降级
    *       null               针对所有服务降级
    * */
    @Override
    public String getRoute() {
        return "item-service";
    }
    /*返回给客户端的降级响应数据
    * 封装到response对象
    * */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {

        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {
                //用来关流
                //BAIS内存数组流，不占用底层系统资源，不需要关闭
                //文件流占用系统文件资源，网络流占用网络资源，数据库流占用数据库资源
            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult --> {Code:500,msg:"调用后台服务出错",data:null}
                String json = JsonResult.err().code(500).msg("调用后台服务出错").toString();
                //将json封装到BAIS
                ByteArrayInputStream inputStream = new ByteArrayInputStream(json.getBytes(StandardCharsets.UTF_8));
                return inputStream;
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders h = new HttpHeaders();
                h.set("Content-Type","application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
